Some of solar cell modules have a structure that is obtained by placing a transparent substrate (glass) on the light receiving surface, aligning and arranging multiple solar cells connected in series or in parallel on the back surface of this transparent substrate, sealing these solar cells with a sealing resin to prepare a solar panel, and then fitting a frame onto the edge portion of the solar panel.
In general, a solar cell module is installed on an architectural structure such as a house and a building and is exposed to wind and weather. Because the solar cell module is a product that is used in such a sever environment, a strength against wind load and snow load provides a measure of product quality. Recently, solar cell modules have been upsized in order to reduce the cost per unit output and save time required for installation and wire connection. Because of this upsizing, the load bearing property has been lowered in the solar panel, especially in its transparent substrate.
A snow load of the snow or the like accumulated on the surface of the solar cell module acts perpendicularly downward, which bends the solar cell module down. As a countermeasure to this, it has been known that, in addition to the frame that surrounds the four sides of the solar panel, a reinforcing frame is provided to span across the frames on the back side of the solar panel and support the solar panel from the back side. With such a structure, it is expected that the amount of deformation of the transparent substrate can be reduced when a load is applied thereto.
Furthermore, in a solar cell module incorporating the reinforcing frame on the back surface of the panel, a shock absorbing member is further attached to the back surface of the panel to prevent the back sheet from wearing and the cells from breaking due to a collision or friction between the back surface of the panel and the reinforcing frame. With such a structure, the back surface of the module would not be in direct contact with the reinforcing frame, and therefore breakage and friction of the back surface of the module can be avoided (see Patent Literature 1, for example).